The present invention relates generally to a system for connecting incoming telephone lines to a telephone answering bank. More particularly, the present invention relates to a system for automatically and efficiently distributing telephone lines to a plurality of operators or one or more automated devices, such as answering machines, voice mail or audiotex systems. Still more particularity, the present invention relates to a control system for assigning operators and/or such devices from a plurality of groups to various telephone lines using historical answering times and/or other criteria to predict operator and/or device availability.
In certain industries, such as merchandise sales, reservation centers, answering services and the like, the ability to effectively handle a large quantity of telephone calls often is the difference between business success and failure. To accommodate customers, typically a large number of telephone lines (or simply "lines") is provided to reduce the number of busy signals and/or the period during which the customer is required to "hold" before their telephone call is answered. The longer that customers are required to wait to have calls answered, the more likely is the probability that customers will hang up before the call is answered. Telephone calls which go unanswered generally correlate to a loss of business. At the same time, it may be prohibitively expensive to hire an operator, or buy a device for each telephone line, especially during periods where all of the telephone lines are not in use.
In an attempt to alleviate this problem, devices have been developed to generally allocate x number of operators or an answering machine to y number of telephone lines, so that a number x of operators or devices can handle a given number y of telephone lines. The term "channel" is used herein to refer generically to any one of the following: an operator, an answering machine, an automated telephone announcement device, an automated telephone answering and recording device, or other similar devices for responding to or recording communications from a call. One such device is commonly referred to as an Automatic Call Distributor ("ACD"), which allocates channels to lines based upon the general principle that the first channel available will be assigned to the line that has waited the longest to be answered. As shown in FIG. 1, this type of prior art ACD unit generally includes a plurality of telephone lines y connected to the ACD unit, which in turn connects to a plurality of channels x. As one skilled in the art will understand, the switching bus typically includes telephone line interface units and isolation circuitry between the ACD and telephone lines. The line interface unit (not shown) detects incoming telephone calls, disconnect signals, and functions to connect an audio or digital path between the telephone line and switching bus.
In these prior art systems, the ACD unit interconnects the telephone lines to the channels through a switching bus, based upon (1) the length of time that the line has been unanswered, and (2) channel availability. Alternatively, some ACD's allocate channels in a manner to ensure that each channel receives an equal number of telephone calls. As shown in FIG. 1, in these type of prior art systems, it is necessary to provide a plurality of independent ACD units to handle multiple channels and lines.
More sophisticated ACD's have been developed that support multiple groups of lines and multiple groups of channels, as generally shown for purposes of illustration in FIG. 2. In these systems, a particular group of lines is assigned to a particular group of channels, with an ACD unit interconnecting the lines and channels. Thus, as shown in FIG. 2, line group A generally is answered by channel group A. If, however, a particular channel group is fully occupied, calls may overflow into another channel group, such as channel group B or channel group C. An ACD controller is provided to monitor channel availability and to direct phone calls between channels as necessary to minimize delays.
Although these prior art ACD systems do minimize delays in answering phone calls, they are not without certain inherent limitations. One particular limitation is that the time value of a call and the period required to answer a call are not considered when redirecting phone calls between channels. For example, if line group A has telephone calls that require five minutes to handle, and these calls are designated as the highest priority so as to take precedence over other calls, they can displace phone calls on another channel group (channel B, for example) which may only require thirty seconds to process. Each call that overflows from line group A therefore potentially preempts ten calls from line group 2. None of the prior art systems recognize this anomaly in their system design, much less provide a viable solution.
Moreover, all of the current ACD systems operate by only looking at current channel availability. There is no system currently available that considers anticipated channel availability real-time, based upon historical answering times for the various groups of lines and/or other parameters indicating future channel availability.
In addition, the prior art systems do not automatically react to anticipated call volume. A call on line group A could overflow to channel group B, where an available channel is located, without regard to the possibility that this channel will be required momentarily by a call on line group 2. In addition, if activity is extremely heavy on line group 1, as may occur during a very heavy peak period, the overflow from line group 1 could occupy a majority of the channels in channel groups B and C, thus adversely affecting the ability to process calls appearing on line groups B and C. The prior art ACD units have no way to automatically guarantee an automatically variable minimum number of channels to each group of lines to insure certain minimum service capacity within each group and still make the group available to handle overflow from other groups.